Vibrating plate mill for batch operation

ABSTRACT

A vibrating plate mill for batch operation comprises a resiliently mounted milling vessel for pulverizing, homogenizing and mixing solids, including abradable materials in the preparation of building materials, chemical products, ceramics and a number of other feeds. The vibrating plate mill further comprises a bob weight driven by a separate electric driving motor rotating about a vertical axis, the bob weight rotating and thereby inducing milling elements in the form of impact plates to rotate in planetary motion inside the milling vessel. The milling vessel is provided with an outlet opening in its floor or its side for discharging the pulverized product, said outlet opening being controllable by a flush closing valve element operable by appropriate means.

1 1 VIBRATING PLATE MILL FOR BATCH OPERATION Gottfried Herzog, 8 An der Landwehr, Osnabruck-Atter, Germany Filed: Feb. 13, 1973 Appl. No.: 331,744

[76] Inventor:

[30] Foreign Application Priority Data Apr. 15, 1972 Germany 7214240 11.8. CI 24l/199.1, 241/202, 241/283 Int. Cl. B026 17/10, B02c 23/02 Field of Search... 241/199, 199.1, l96.6l99.7, 241/202-203, 205, 170-171, 175,184, 60, 262, 270-271, 283, 169

[56] References Cited 6/1947 Chott 241/175 6/1942 Chott 241/175 11/1961 Udy 241/170 [451 Oct. 8, 1974 3,346,200 10/1967 Lesin 241/171 3,552,068 1/1971 Fossen 241/175 X 3,762,659 10/1973 Aegidius 241/199 Primary Examiner-Granville Y. Custer, Jr. Assistant Examiner-Howard N. Goldberg Attorney, Agent, or Firm-Markva & Smith 57] ABSTRACT A vibrating plate mill for batch operation comprises a resiliently mounted milling vessel for pulverizing, homogenizing and mixing solids, including abradable materials in the preparation of building materials, chemical products, ceramics and a number of other feeds. The vibrating plate mill further comprises a bob weight driven by a separate electric driving motor rotating about a vertical axis, the bob weight rotating and thereby inducing milling elements in the form of impact plates to rotate in planetary motion inside the milling vessel. The milling vessel is provided with an outlet opening in its floor or its side for discharging the pulverized product, said outlet opening being controllable by a flush closing valve element operable by appropriate means.

9 Claims, 1 Drawing Figure VIBRATING PLATE MILL FOR BATCH OPERATION BACKGROUND OF THE INVENTION This invention relates to a vibrating plate mill for batch operation.

Diverse forms of construction and types of vibrating mills are already known in'the art.

ends are anchored in a foundation. Near their ends carrying the milling vessel there is an assembly of electromagnets which cyclically deflects at least one spring rod in a transverse direction to its longitudinal axis. By the provision of several electromagnets and several spring rods the milling vessel can be induced to perform gyrating circular movements in a horizontal plane. By appropriately adjusting the relative power of the electromagnets vibratory movements in paths of other configurations, such as elliptical vibrations, can also be generated. These known types of vibration mill are restricted to performing vibratory motions in a single plane only, i.e., in two coordinates of space.

In other size-reducing devices the milling vessel has the form of a long narrow shaft which vibrates in a vertical plane, and which is filled with impact elements such as rods, the feed to be pulverized travelling in a direction normal to the vibrations and being crushed by the rods before leaving the milling vessel through a floor resembling a screen. The milling vessel rests on supporting springs and vibrates at a high rate, each point of the milling vessel travelling in an arcuate path.

In other known vibrating mills the milling vessel performs vibratory motions in circular or elliptical paths contained in a horizontal plane. The milling vessels contain ring-shaped grinding elements, the feed being conducted into their inside grinding path. The sizebrating table is attached to an underframe by elastic elements, such as metal or rubber springs, a shaft mounted in the underframe provided with eccentrically located pins engaging the carrier plate and bearing a counterweight on the opposite side to the pins. When the vibrating table is operated the coil springs supporting the carrier plate vibrate in two directions, namely on the one hand the end of each coil spring moves in a circle around the spring axis and on the other hand the coil spring vibrates longitudinally in the direction of its axis. The vibrated feed is therefore subjected to an impulse having one horizontal and one vertical component. so that a thorough commixture of the feed is achieved. These prior art arrangements have the drawback that the connection between the drive shaft and the eccentric associated with the carrier plate, which must necessarily participate in the nutating motions of the carrier plate, experiences very considerable wear.

Finally inertial vibrating conveyors have been proposed which concentrically embrace one or more feeding or discharging points and perform rapidlow amplitude vibrations induced by several rotating out-ofbalance inertial weights. The conveyor or screening trough is energized by the bob weights on each side rotating with a relative phase displacement of so that the trough vibrates about a virtual axis in the middle between the bob weights. Since the conveyor trough is supported by springs which are so disposed that the direction of vibration is tangential to the circle, the vibrations of the conveyor trough are not in the plane of this circle but slightly inclined in relation thereto. However, these conventional devices are unsuitable to be employed for the size reduction of a feed.

Furthermore, for fine milling, an apparatus has been proposed which contains a rapidly vibrating body in the interior of a rotating drum. The feed adheres by centrifugal force to the wall of the drum and the vibrating body is resiliently mounted at each end and is thus itself designed to generate vibrations, or a vibrator may be contained in its interior. It is a defect of this arrange ment that the considerable grinding effect on the feed causes a correspondingly high rate of wear of the vibrating body, so that the product is unevenly ground. Even continuous readjustment of the amplitude of vibration and of the several consequential parameters cannot eliminate the described defect.

For fine milling so-called vibrating plate mills have also been proposed. These consist of a cylindrical milling vessel containing milling elements, one or more rings and a stone. The cylindrical milling vessel is induced to perform rotary vibrations by a bob weight mounted on the vertical drive shaft of a motor. The milling elements inside the cylindrical milling vessel are forced to perform planetary gyrations and they grind and break down the feed which is introduced at a rate bearing a fixed relationship to the capacity of the milling vessel. The milling operation proceeds in batches, the milling vessel being charged and discharged by manual control. In view of the requirements of up-todate technology the need for manual control is a drawback.

Furthermore, vibrating plate mills have been proposed which, though based on the above-described principle of operation, permit milling to be carried out in continuous process. In this form of construction the milling vessel is provided in its external circumference with openings for discharging the feed when this has been reduced to a given grain size. The milling vessel is still charged manually but the discharge of the product is automatic. It is an objection to this form of construction that size reduction is confined to the upper fine milling range, i.e., to grain sizes above 60 microns. Another shortcoming is that the range of grain size scatter cannot be controlled. Finally, it must be considered a defect that a specific batch, i.e., a defined quantity of feed, cannot be thus milled.

SUMMARY OF THE INVENTION In view of the described state of the art the object of the invention is to enlarge the range-of available vibrating plate mills by an improved form of construction in which the above criticized shortcomings are eliminated and a feed can be automatically size-reduced in batches.

To attain this object the present invention provides a vibrating plate mill for batch operation, which comprises a resiliently mounted milling vessel for pulveriz- 3 ing, homogenizing and mixing solids, including abradable materials in the preparation of building materials, chemical products, ceramics and a number of other feeds; a bob weight driven by a separate electric driving motor rotating about a vertical axis, said bob weight performing vibratory gyrations and thereby inducing milling elements in the form of impact plates to rotate in planetary motion inside the milling vessel; a charging hopper surmounting the milling vessel, and an outlet opening in thefloor or side of the milling vessel for discharging the pulverized product being controllable by a flush closing valve element operable by appropriate means.

The means for operating the valve element controlling the outlet opening may have the form of pneumatic or hydraulic actuating cylinders, electric lifting magnets or like actuating means which are operable via pressure pipes, time switches or the like. The valve element may be attached to the piston rod of a piston head controllably movable inside the actuating cylinder.

Furthermore, the outlet opening of the milling vessel may directly communicate with a descending discharge pipe for the product.

BRIEF DESCRIPTION OF THE DRAWING An embodiment of the invention will now be described by way of example and with reference to the accompanying drawing in which the only FIGURE is a longitudinal middle section of a vibrating plate mill according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing illustrates a vibrating impact plate mill having a vibrator unit which comprises an electric driving motor 12 and a bob weight 13 in a casing 14 that is freely pendantly suspended from compression springs 11 surmounting a machine frame 10. The bob weight 13 driven by the electric driving motor 12 causes a cylindrical milling vessel 1 containing a grinding chamber 18 to build up a circular vibrating motion. Consequently the milling elements 15 (one or more rings and a stone) of the vibrating plate mill perform planetary gyrating motions and by impact pulverize a feed introduced into the milling vessel 1 through a charging hopper 2. According to the invention the feed is introduced into the milling vessel 1 by pneumatic conveyor means.

The speed of rotation of the driving motor 12 can be adjustably controlled. A valve element is closed during the milling operation and forms a flush closure in an outlet opening 3 in the floor of the milling vessel 1 and thus prevents portions of the feed from catching or being retained in the outlet opening 3. A cylinder 4 which contains a piston head 8' attached to a piston rod 8 formed integrally with the valve element 5 is detachably bolted to the milling vessel 1.

When a prescribed milling time has elapsed the valve element 5 is opened. In the illustrated embodiment this is done in that a pressure medium which had previously entered the cylinder 4 through a pressure pipe 6 and which had thus kept the valve closed is now introduced into the cylinder 4 through a pressure pipe 7. This pressure medium which may be oil or compressed air flows into the interior of the cylinder 4 and now forcesv the piston head 8' to descend. Since the piston head 8, the piston rod 8 and the valve element 5 form a single unit the outlet opening 3 in the bottom of the milling-vessel 1 will be opened, allowing the pulverized feed to be discharged through the outlet opening 3 into an inclined discharge pipe 9. The valve element 5 can be closed in analogous manner by reintroducing the pressure medium into the interior of the cylinder 4 through the pressure pipe 6.

Before the milling vessel 1 is refilled with a predetermined quantity of the feed, its interior is flushed out and dried with hot air. For this purpose a cover plate 16 which forms a dust-tight closure on the charging hopper 2 as well as the milling vessel 1 are both fitted with suitable connections 17 for the necessary pipes. When the flushing and drying process has been completed the cover plate 16 is taken off, the outlet open-. ing 3 is closed by the valve element 5 and a fresh batch of feed is filled into the milling vessel 1, so that the described working cycle can repeat itself.

Contrary to the state of the art the illustratively described vibrating plate mill permits a feed to be pulverized in a fully automated process. This novel facility effectively enriches the conventional technology in the field of vibrating plate mills used for analytical purposes.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiment is therefore to be considered in all respects as illustrative and not restrictive.

What is claimed is:

1. A vibrating plate mill for batch operation, comprising a resiliently mounted milling vessel for pulverizing, homogenizing and mixing solids, including abradable materials in the preparation of building materials, chemical products, ceramics and a number of other feeds; a bob weight driven by a separate electric driving motor rotating about a vertical axis, said bob weight rotating and causing said milling vessel to perform vibratory gyrations and thereby inducing milling elements inside said milling vessel to rotate in planetary motion; a charging. hopper surmounting the milling vessel, and an outlet opening in the floor of the milling vessel for discharging the pulverized product being controllable by a flush closing valve element operable by appropriate means.

2. A vibrating plate mill according to claim 1,

wherein said means for operating the valve element controlling the outlet opening have the form of fluid actuating cylinders operable via pressure pipes.

3. A vibrating plate mill according to claim 2, wherein the valve element is attached to the piston rod of a piston head controllably movable inside the actuating cylinder.

4. A vibrating plate mill according to claim 1, wherein the outlet opening of the milling vessel directly communicates with a descending discharge pipe.

5. A vibrating mill for pulverizing, homogenizing and mixing solids comprising a base, a frame and resilient means mounting said frame on said base, said frame including a. a milling vessel having a floor and wall means about the perimeter thereof transverse to said floor,

b. at least one milling element in said vessel, said element being free to move about said vessel,

c. means for feeding material into said vessel,

d. an outlet opening for discharging batches of pulverized product,

e. valve means for opening and closing said outlet,

f. means for operating said valve means,

g. weight means mounted for eccentric movement about an axis transverse to the floor of said vessel, and

h. drive means for rotating said eccentric weight means,

i. whereby said rotating eccentric weight means causes said milling vessel to revolve inducing said milling element to move in a planetary motion inside said milling vessel.

6. A mill according to claim 5 wherein said milling vessel is cylindrical and said milling elements comprise at least one annular ring member and a cylindrical 8. A mill according to claim 7 wherein said means for operating said valve means comprises a fluid operated piston-cylinder arrangement.

9. A mill according to claim 8 further comprising a charging hopper for feeding material into said milling vessel and a descending discharge pipe connected to said outlet opening. 

1. A vibrating plate mill for batch operation, comprising a resiliently mounted milling vessel for pulverizing, homogenizing and mixing solids, including abradable materials in the preparation of building materials, chemical products, ceramics and a number of other feeds; a bob weight driven by a separate electric driving motor rotating about a vertical axis, said bob weight rotating and causing said milling vessel to perform vibratory gyrations and thereby inducing milling elements inside said milling vessel to rotate in planetary motion; a charging hopper surmounting the milling vessel, and an outlet opening in the floor of the milling vessel for discharging the pulverized product being controllable by a flush closing valve element operable by appropriate means.
 2. A vibrating plate mill according to claim 1, wherein said means for operating the valve element controlling the outlet opening have the form of fluid actuating cylinders operable via pressure pipes.
 3. A vibrating plate mill according to claim 2, wherein the valve element is attached to the piston rod of a piston head controllably movable inside the actuating cylinder.
 4. A vibrating plate mill according to claim 1, wherein the outlet opening of the milling vessel directly communicates with a descending discharge pipe.
 5. A vibrating mill for pulverizing, homogenizing and mixing solids comprising a base, a frame and resilient means mounting said frame on said base, said frame including a. a milling vessel having a floor and wall means about the perimeter thereof transverse to said floor, b. at least one milling element in said vessel, said element being free to move about said vessel, c. means for feeding material into said vessel, d. an outlet opening for discharging batches of pulverized product, e. valve means for opening and closing said outlet, f. means for operating said valve means, g. weight means mounted for eccentric movement about an axis transverse to the floor of said vessel, and h. drive means for rotating said eccentric weight means, i. whereby said rotating eccentric weight means causes said milling vessel to revolve inducing said milling element to move in a planetary motion inside said milling vessel.
 6. A mill according to claim 5 wherein said milling vessel is cylindrical and said milling elements comprise at least one annular ring member and a cylindrical stone.
 7. A mill according to claim 6 wherein said outlet opening is in the floor of said milling vessel and said valve means comprises a plug and means to guide said plug between a closed position in said outlet opening and an open position, a surface of said plug being flush with said floor when said plug is in said closed position.
 8. A mill according to claim 7 wherein said means for operating said valve means comprises a fluid operated piston-cylinder arrangement.
 9. A mill according to claim 8 further comprising a charging hopper for feeding material into said milling vessel and a descending discharge pipe connected to said outlet opening. 